Polyamide-imide resin is a resin material which is superior in heat resistance and mechanical strength and has a self-lubricating property. Therefore, polyamide-imide resin is often used in slide members of a variety of devices.
Each slide member has a substrate, and a sliding layer comprising a solid lubricant and a polyamide-imide resin which serves as a binder for holding the solid lubricant, as disclosed in Japanese Unexamined Patent Publication No. 11-13638, for instance. Generally, such a sliding layer can be obtained by coating a sliding surface side of the substrate with a coating composition in which a solid lubricant is mixed with a resin varnish.
Besides, some slide members are produced by injection molding a molding material in which a polyphenylene sulfide resin or a polyarylene sulfide resin is mixed with a polyamide-imide resin. For example, Japanese Unexamined Patent Publication No. 2001-302914 mentions a sliding ring formed of a resin composition in which a molding material comprising a polyamide-imide resin and a polyarylene sulfide resin is made to contain an organoclay composite prepared by modifying a swellable layered silicate with organic cations. However, since injection molding is to pour a material melted by heating into a mold and mold the material, injection molding has no degree of shape freedom, cannot produce sliding component parts which need to have a thin sliding layer, and has a difficulty in ensuring adhesiveness to other component parts. Besides, when the abovementioned blended polymers are molded by injection, since the polyamide-imide resin as a matrix and polymers blended into the matrix are different from each other, resultant moldings deteriorate in both mechanical characteristics and heat resistance due to the influence of the blended polymers.
Moreover, in recent years, there has been a demand for a further improvement in characteristics of slide members so as to ensure more reliability than ever.